However the number of steam injectors and the volume

Info icon This preview shows pages 2–3. Sign up to view the full content.

View Full Document Right Arrow Icon
However, the number of steam injectors and the volume of steam being injected would continue to grow dramatically from 1973 through 1985. Steamflood injection volumes increased by another factor of 4.4, to nearly 1.9 million BSPD, and the number of steam injectors increased from 1136 to 5001 (Figures 1 and 3). Total Steam Injection During these growth years, oil prices increased greatly. There was a small price drop in 1982, but prices were stable in 1983-1985. This high price environment encouraged rapid expansion. Steam injection grew at a rate of nearly 11% per year during this period, essentially all in the form of increased steamflood injection. The percentage of steam used in steamflood projects grew from 15% to 85% during this period, and steamflooding continues to account for 80% of steam injection (Figure 4). California reached its peak steam injection rate in 1985. Combined cyclic and steamflood injection that year was 2.07 million BSPD into 13,798 wells. There were 8794 cyclic stimulation wells and 5001 steamflood injectors. Achieving Maturity In 1986 California heavy oil prices collapsed from a value of $20/barrel to less than $9/barrel. Steam injection rates began a general downward trend which has continued to the present. There was not an immediate drop in thermal oil production, as recently expanded steamflood areas were in the early stages of production response. Maximum thermal recovery oil production was reached in 1988 at 511,000 BOPD, after which it began a steady decline (Figure 5). This combination of stable or declining production and lower prices forced operators to more closely examine their operating procedures. Although California’s average steam/oil ratio (SOR) had dropped somewhat from its peak due to production response from immature steamfloods, it was still nearly 4.5 when the 1986 price collapse began. Since generating steam is the largest operating expense item in a steamflood, efficient use of steam began to receive much more attention. This emphasis has continued to the present, and has become even more critical as larger numbers of projects pass their peak production period. Heat Management Optimization of heat use in a steamflood requires an understanding of the physics which govern the process and having methods in place to adequately monitor and analyze those factors. The early analytical tools available to steamflood designers for estimating heat losses and the growth of the steamchest were based upon frontal advance theory, e.g. , Marx and Langenheim 4 , and Myhill and Stegemeier 5 . With the frontal advance concept, higher steam injection rates both reduce ultimate heat losses to the underburden and overburden, and result in a more rapid recovery of oil. Thermal observation wells were drilled in early projects to provide verification of the rate of advance of the steam as predicted by the frontal advance models. However, post-flood cores taken to evaluate early pilots showed that gravity override was a significant factor 6 . Thus, there was significant inconsistency between the analytical models and the physics of the process (Figure 6). However, many engineers still
Image of page 2

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern